Methods and apparatus for hemostasis following arterial catheterization

ABSTRACT

A method for accelerating hemostasis of an artery having a puncture after arterial catheterization, the catheterization using a catheter introducer, the method including the steps of inserting into an artery a catheter introducer prior to arterial catheterization, following arterial catheterization, introducing a hemostasis device into the catheter introducer, such that a forward end of the hemostasis device lies exterior of the artery adjacent a puncture in a wall of the artery, accelerating hemostasis by heating blood in the vicinity of the puncture, thereby shortening the time required for hemostasis and following hemostasis, removing the catheter introducer and hemostasis device from the patient. A method for monitoring the progress of hemostasis of an artery is also disclosed.

Applicant's U.S. Pat. Nos. 5,728,134 and 6,048,358, and published PCTApplications WO 98/11830 and WO 00/02488 describe methods and apparatusfor hemostasis which greatly simplify hemostasis and thus greatly reducepatient discomfort following arterial catheterization. These patentdocuments, the disclosures of which are hereby incorporated byreference, and the prior art referenced therein are considered torepresent the state of the art.

FIELD OF THE INVENTION

The present invention relates to methods and apparatus for hemostasisfollowing arterial catheterization.

BACKGROUND OF THE INVENTION

Various techniques are known for arterial catheterization. Followingarterial catheterization, it is necessary to promote hemostasis quicklyand without undue hardship for the patient.

SUMMARY OF THE INVENTION

The present invention seeks to provide improved apparatus and techniquesfor measuring the progress of and accelerating hemostasis.

There is thus provided in accordance with a preferred embodiment of thepresent invention a method for monitoring the progress of hemostasis ofan artery having a puncture after arterial catheterization, thecatheterization using a catheter introducer, the method including thesteps of inserting into an artery a catheter introducer prior toarterial catheterization, following arterial catheterization,introducing a hemostasis device into the catheter introducer, such thata forward end of the hemostasis device lies exterior of the arteryadjacent a puncture in a wall of the artery, during hemostasis,measuring the heat conductivity of blood in the vicinity of thepuncture, thereby to provide an output indication of the progress ofhemostasis and following hemostasis, removing the catheter introducerand the hemostasis device from the patient.

Preferably, the method also includes inflating a balloon attached to thecatheter introducer to block the puncture, prior to the introducing ahemostasis device. Additionally, the removing the catheter introduceralso includes deflating the balloon prior to removing the catheterintroducer.

There is also provided in accordance with another preferred embodimentof the present invention a method for accelerating hemostasis of anartery having a puncture after arterial catheterization, thecatheterization using a catheter introducer, the method including thesteps of inserting into an artery a catheter introducer prior toarterial catheterization, following arterial catheterization,introducing a hemostasis device into the catheter introducer, such thata forward end of the hemostasis device lies exterior of the arteryadjacent a puncture in a wall of the artery, accelerating hemostasis byheating blood in the vicinity of the puncture, thereby shortening thetime required for hemostasis and following hemostasis, removing thecatheter introducer and hemostasis device from the patient.

In accordance with another preferred embodiment of the present inventionthe method also includes inflating a balloon attached to the catheterintroducer to block the puncture, prior to the introducing a hemostasisdevice. Additionally, the removing the catheter introducer also includesdeflating the balloon prior to removing the catheter introducer.

Alternatively or additionally, the method also includes measuring theheat conductivity of blood in the vicinity of the puncture duringhemostasis, thereby to provide an output indication of the progress ofhemostasis.

There is further provided in accordance with still another preferredembodiment of the present invention a hemostasis device including aresistance element, disposed at a forward end of the hemostasis device,a resistance sensor and a resistance indicator, operative to provide anindication of the resistance at the resistance sensor.

In accordance with another preferred embodiment of the presentinvention, the hemostasis device also includes a power supply seriallyconnected to the resistance element, the resistance sensor and theresistance indicator. Preferably, the power supply is operative tosupply a high level current to the resistance element. Alternatively,the power supply is operative to supply a low level current to theresistance sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description taken in conjunction with thedrawings in which:

FIGS. 1A and 1B are simplified pictorial illustrations of respectivefirst and second modes of operation of a hemostasis device constructedand operative in accordance with a preferred embodiment of the presentinvention;

FIG. 2 is a simplified pictorial illustration of the hemostasis deviceof FIGS. 1A and 1B during hemostasis; and

FIGS. 3A and 3B are graphs illustrating the typical conductivity levelsmeasured by the hemostasis device when used in the operating modes shownin FIGS. 1A and 1B, respectively.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Reference is now made to FIGS. 1A and 1B, which are simplified pictorialillustrations of a preferred embodiment of a hemostasis device inrespective first and second modes of operation.

As seen in FIG. 1A, a hemostasis device 10 is inserted into a catheterintroducer 11, following arterial catheterization and withdrawal of acatheter (not shown), such that a forward end 12 of the hemostasisdevice 10 lies adjacent to and outside a puncture 14 in an artery 16. Atleast one external balloon 18 is preferably disposed adjacent catheterintroducer 11 and is shown in an inflated orientation, wherein theballoon 18 forms a skirt surrounding and sealing puncture 14 from thetissue external thereto. At this stage blood normally fills artery 16 aswell as puncture 14, as well as the annular volume 20 surrounded byballoon 18 adjacent puncture 14 and forward end 12.

In accordance with another preferred embodiment of the presentinvention, the at least one balloon 18 need not be provided.

In accordance with a preferred embodiment of the present invention, aresistance element 22 is disposed at a forward edge 24 of the forwardend 12, and is coupled in series with an external power supply 26 viaconductors 28, which typically extend along the length of the hemostasisdevice 10. Preferably, the series connection includes a resistanceindicator 30, which provides an indication of the resistance at aresistance sensor 32.

As seen in FIG. 1A, a low level current, typically less than 0.1 ampere,is provided by external power supply 26 to enable the resistanceindicator 30 to monitor the progress of hemostasis, to allow for timelyremoval of catheter introducer 11 and hemostasis device 10 from thepatient.

It is appreciated that the heat conductivity of the blood in liquid formis measurably different from that of a blood clot formed duringhemostasis, as will be described hereinbelow with reference to FIGS. 3Aand 3B.

FIG. 1B illustrates the hemostasis device of FIG. 1A in a secondpreferred mode of operation. As shown in FIG. 1B, a high levelelectrical current, typically greater than 0.1 ampere, is supplied viathe external power supply 26 to resistance element 22. The provision ofthis current causes heating of the blood adjacent to the resistanceelement 22 and provides for accelerated hemostasis. The provision ofresistance indicator 30, connected to resistance sensor 32, enables themonitoring of the progress of the accelerated hemostasis, to allow forregulation of the current provided to resistance element 22 over time,and to allow timely removal of catheter introducer 11 and hemostasisdevice 10 from the patient.

It is appreciated that the heat conductivity of the blood in liquid formis measurably different from that of a blood clot formed duringhemostasis, as will be described hereinbelow with reference to FIGS. 3Aand 3B.

Reference is now made to FIG. 2, which is a simplified pictorialillustration of hemostasis device 10 of FIGS. 1A and 1B duringhemostasis.

FIG. 2 shows the hemostasis device 10 of FIGS. 1A and 1B and illustratesthe different heat conductivity of the blood during the various stagesof hemostasis. As seen in FIG. 2, the blood flowing through the artery16 and adjacent the puncture 14 in the artery is in liquid form, whereits heat conductivity is greater than that of the blood 40 which hasbegun to coagulate. Blood 40 is in a viscous form, which has a heatconductivity greater than that of the blood 42, which has already begunto solidify into a blood clot. Resistance sensor 32 is thus able tomeasure the process of coagulation by measuring the heat conductivity ofthe adjacent blood.

Reference is now made to FIGS. 3A and 3B, which are graphs illustratingthe typical conductivity levels measured by the catheter introducerassembly when used in the operating modes shown in FIGS. 1A and 1B,respectively.

FIG. 3A shows the heat conductivity of the blood over time, in the modeof operation illustrated in FIG. 1A, where the blood is in a liquid format time T₀, with relatively high heat conductivity, where the heatconductivity decreases gradually over time as the blood forms a clot attime T_(H).

FIG. 3B shows the heat conductivity of the blood over time, in the modeof operation illustrated in FIG. 1B, where the blood is heated toaccelerate clotting. As seen in FIG. 3B, the heat conductivity begins attime T₀ in a liquid form with relatively high heat conductivity, whichdecreases rapidly as the blood is heated and the clotting occurs at anaccelerated rate. FIG. 3B also shows the heat conductivity curve overtime shown in FIG. 3A, which clearly illustrates the acceleratedhemostasis described in reference to FIG. 1B hereinabove, where T_(HA)is the accelerated hemostasis time and T_(H) is the non-acceleratedhemostasis time.

It will be appreciated by persons skilled in the art that the presentinvention is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove as well as variations and modifications whichwould occur to persons skilled in the art upon reading the specificationand which are not in the prior art.

1. A method for monitoring the progress of hemostasis of an arteryhaving a puncture after arterial catheterization, said catheterizationusing a catheter introducer, the method comprising the steps of:inserting into an artery a catheter introducer prior to arterialcatheterization; following arterial catheterization, introducing ahemostasis device into said catheter introducer, such that a forward endof said hemostasis device lies exterior of the artery adjacent apuncture in a wall of the artery; during hemostasis, measuring the heatconductivity of blood in the vicinity of said puncture, thereby toprovide an output indication of the progress of hemostasis; andfollowing hemostasis, removing said catheter introducer and saidhemostasis device from the patient.
 2. A method for monitoring theprogress of hemostasis according to claim 1 and also comprisinginflating a balloon attached to said catheter introducer to block saidpuncture, prior to said introducing a hemostasis device.
 3. A method formonitoring the progress of hemostasis according to claim 2 and whereinsaid removing said catheter introducer also comprises deflating saidballoon prior to removing said catheter introducer.
 4. A method foraccelerating hemostasis of an artery having a puncture after arterialcatheterization, said catheterization using a catheter introducer, themethod comprising the steps of: inserting into an artery a catheterintroducer prior to arterial catheterization; following arterialcatheterization, introducing a hemostasis device into said catheterintroducer, such that a forward end of said hemostasis device liesexterior of the artery adjacent a puncture in a wall of the artery;accelerating hemostasis by heating blood in the vicinity of saidpuncture, thereby shortening the time required for hemostasis; andfollowing hemostasis, removing said catheter introducer and hemostasisdevice from the patient.
 5. A method for accelerating hemostasis of anartery according to claim 4 and also comprising inflating a balloonattached to said catheter introducer to block said puncture, prior tosaid introducing a hemostasis device.
 6. A method for acceleratinghemostasis of an artery according to claim 5 and wherein said removingsaid catheter introducer also comprises deflating said balloon prior toremoving said catheter introducer.
 7. A method according to claim 4 andalso comprising measuring the heat conductivity of blood in the vicinityof said puncture during hemostasis, thereby to provide an outputindication of the progress of hemostasis.
 8. A hemostasis devicecomprising: a resistance element, disposed at a forward end of saidhemostasis device; a resistance sensor; and a resistance indicator,operative to provide an indication of the resistance at said resistancesensor.
 9. A hemostasis device according to claim 8 and also comprisinga power supply serially connected to said resistance element, saidresistance sensor and said resistance indicator.
 10. A hemostasis deviceaccording to claim 9 and wherein said power supply is operative tosupply a high level current to said resistance element.
 11. A hemostasisdevice according to claim 9 and wherein said power supply is operativeto supply a low level current to said resistance sensor.